Generally, a movement line of a moving body such as person or object is detected by associating a position of the moving body with identification information on the moving body. Various techniques for movement line detection are proposed (see PLTs 1 and 2, for example).
For example, a multipurpose tracking device described in PLT 1 is connected to a radar device for outputting position information on an object to be tracked (elevation, azimuth and distance) and a target identification sensor device for outputting identification information and a position (elevation and azimuth) of the object to be tracked. The multipurpose tracking device described in PLT 1 links the position information output by the radar device thereby to generate a group of hypotheses including a wake of the target. The multipurpose tracking device generates an angle wake indicating an orientation in which the target is moving by use of the information output by the target identification sensor device. Further, the multipurpose tracking device sorts out the hypotheses included in the group of hypotheses by calculating a similarity between each hypothesis and each angle wake. The multipurpose tracking device also reduces the group of hypotheses by deleting less reliable hypotheses and integrating similar hypotheses.
A system described in PLT 2 defines trajectory candidates which are assumed to express a trajectory of an individual moving body, and generates hypotheses based on a pair of trajectory candidate and identification information of the moving body. The system calculates a likelihood at which identification information is detected for each trajectory candidate included in an individual hypothesis, and estimates a maximum-likelihood hypothesis based on the likelihood. The trajectory candidate is generated based on segments of the detected trajectory.